Auður Gauksdóttir¹

Ólafur Árni Sveinsson^1,2

¹Faculty of Medicine, University Iceland, ²Department of Neurology, University Hospital of Iceland, Reykjavík.

Correspondence: Ólafur Árni Sveinsson, olafursv@landspitali.is

Key words: transient global amnesia, anterograde amnesia, hippocampus, diffusion weighted imaging, hypertension, migraine.

BACKGROUND: Transient Global Amnesia (TGA) is a benign syndrome characterized by sudden anterograde memory loss, that resolves spontaneously within 24 hours. TGA appears without other focal neurological symptoms. The aim of this study was to study TGA in the greater Reykjavik-area.

METHODS: We retrospectively analysed the medical history of patients with a diagnosis of TGA (ICD-10 G45.4) at the University Hospital in Iceland in 2010-2021. Medical records were reviewed, and information about year and age at diagnosis, sex, symptoms, precipitating events, imaging results and risk factors were collected. Statistical processing was performed with Excel and Rstudio.

RESULTS: Overall, 348 attacks of TGA were identified with a mean frequency of 29 attacks/year, where 9.9% had an earlier history of TGA. The mean age was 64.1, with 50% of subjects between 58-70 years old. The sex distribution was equal (49.9% female). Possible precipitating events were found in 53.7% of cases, with physical activity being the most common one (24.4%), followed by sudden temperature change and emotional stress. In 96% of patients a computerized tomography was performed (no sign of acute changes were found), and magnetic resonance imaging (MRI) in 36.2% of cases. MRI showed restricted diffusion in the hippocampal area in 10.3% of cases.

DISCUSSION: TGA is not a rare but a benign syndrome. Our findings regarding age, sex distribution and precipitating events were in accordance with other studies. TGA is thought to result from a temporary hippocampal dysfunction supported by the clinical presentation and MRI findings. The cause of TGA is however still unknown.